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(No Model.)

0. L. BUOKINGHAM' 82; H. C. TOWNSEND.

ELECTRIC ARC LAMP No. 293,944. Patented Feb. 19, 1884.

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UNITED, STATES CHARLES L. BUOKINGHAM AND HENRY G. TOXVNSEND, OF NE ELECTRIC- SPECIFICATION forming part of To (Z5 whom, it may concern.-

Be it known that we, 0. L. BUCKINGHAM and H. O. TOWNSEND, of the city, county, and State of New York, citizens of the State of New York, jointly have invented a new and useful Improvement relating to Cut-Outs for Electric-Arc Lamps, of which the following is a specification; and this application we desire to designate as Case 0.

In another application for a patent, desig nated as Case A, of even date herewith, we have described and claimed a cut-out for an electric-arc lamp consisting of a normally-open branch around the are, which is periodically I 5 closed, and means for retaining said branch closed in case of a predetermined arc-resistance.

Our present invention is a modification of the foregoing, in that, instead of employing the periodically-closed branch, when retained closed, for the safety short-circuit around the are, we merely employ the periodically-closed shunt or branch to divert current from the arc branch, thereby, in case of a high arc-resistance, so far demagnetizing the electro-magnets in the are branch as to cause them to release their armatures and close a second shunt of low resistance around the are as well as-fecd the carbon.

lVe will now describe our invention by reference to the accompanying drawings.

At a point, a, of the main line L the circuit is divided into three branches, viz Branch 6 and 7 is periodically closed by spring '1 and 3 5 a circuit-breaking wheel, K, whose periphery Q, excepting metallic part J, is of insulating material. Circuit-breaker K is rotated by a clock-train or other motor. Branch 1 and 5 embraces the coils of eleetro-magnets M and h and the arc of the lamp. Branch 10 11 12 is completed by two armaturelevers, A and B, when the former is at its front stop and the latter at back contact. If considerable resist ance were employed in branch 10, 11, and 12,

4 5 we might dispense with armature A and electro-magnet N. However, if there were little or no resistance in said branch, the lamps could not be readily relighted after a complete cessation of current on the line, since, if the ourrent were wholly arrested, the branch being of little resistance, and armature B being at back contact, almost the entire current would PATENT YORK, N. r,

ARC'LAMP.

Letters Patent No. 293,944, dated February 19, 1884. Application filed August 15, 1883. (No model.) 7

I be diverted from the are branch, and not enough current would flow therein to cause armature B to break branch 10 11 12, even if the carbons C C were in contact. Therefore, if the resistance of branch 10 11 12 be very low. it is an essential condition that upon an entire cessation of current in circuit said branch be left open. Now, armature A is so adjusted as to be attracted to N by a very weak current, and the armature will only be retracted by its spring in case of almost an entire absence of current; but when an absence I of current has occurred armature A will be retracted, and a current sent to line will not, primarily, pass through the shunt branch, but I will flow through the are branch, therebycausing armature B to leave back contact before A has arrived atits front stop, thus insuring the breaking of the shunt branch at the starting of the lights. Circuit-breaker K is continuously rotated. Thus the periodically-closcd branch 6 7 is never closed longer than for an instant at a time. It will be seen, however, that, if there were a high arc-resistance at any periodic closing of branch 6 T, enough current during that brief time of closing would be diverted from the are branch and cleetro-magnet M to permit armature-bar B to be retract ed to its back contact, and there close a short circuit around the are; nor would the subsequent periodic closings of branch 5 '7 have any influence to attract armature B, and thereby break the short-circuit. \Vhen contact is established between T and J, the arc branch will not be cut out unless the resistance of the are be great; if great, enough current will be di- Verted from the are branch to partially demagnetize M, and thereby enable the retraction of armature B; if not great enough, cur rent will still flow through the coils of M to prevent armature-bar B from falling to back contact, and to thereby short-eircuit the are. If the resistance of the are be great, armature B will close the short-circuit; and although the periodically-closed shunt be immediately broken, owing to the establishment of a new path of lower resistance around the are, not enough current 'will flow through the are branch to attract armature B and break the short-circuit. XVhen the short-circuit through B has once been formed, it will not again be broken until the arc-resistance is removed,

and the removal of arc-resistance will not of.

itself cause the attraction of armature-lever B and the breaking of the short-circuit. To effeet the breaking of said short-circuit, it must be provided with sufficient resistance to force considerable current through the arc branch after reestablishment of contact between the carbons. If the short-circuit have very little or practically no resistance, the short-circuit, when once made, can only be broken by an at tendants visiting the lamp and moving B by hand.

M is an clectromagnet having an axial armature and carbon-holder of any well-known form.

Vhat we claim, and desire to secure by Letters Patent, is-

'1. In an electric lamp, the combination of an arc branch including the coils of a circuitcontrolling electro-magnet, a normally-open branch around the are, having a circuit-closer for occasionally closing the same, and another branch for shortcircuiting the lamp, and means for closing said short-circuitin g branch, said means being brought into operation by a diversion of current from the arc branch through the branch of the periodic circuitcloser.

2. The combination of a periodic circuitcloser in a normally-open branch around the arc of an electric lamp, an electro magnet in the are branch, whose magnetism is weakened by a diversion of current through the periodically-closed branch, a second branch of low resistance for short-circuiting the lamp, and means brought into action to close said shortcircuiting branch upon a diminution of magnetism in the arc-branch electro-magnet.

3. In an electric lamp, a safety short-circuit around the are, and an armature-lever for closing the same when at back contact, an electro-magnet in thearc branch for controlling said circuit-closing arm, a periodically-closed branch to divert current from the are branch and to thereupon cause the closing of the cutout branch, and means for causing the feed of the carbons by diversion of current from said are branch.

4. In an electriclamp, a safety shunt-circuit around the are, and an armature-lever for closing said shunt-circuit, an electro-magnet in the are branch for controlling said armature-lever, another branch around the arc of sufficiently low resistance to divert enough current from,

the are branch to permit the armature of the electro-magnet therein to close the short-circuiting or cut-out branch.

5. An electromagnct, N, whose coils are in the main line, and its armature A forming part of the short-circuiting branch, an armaturelever, B; and electro-magnet M, whose coils are in the arc branch, for controlling armaturelever B, as and for the purpose described.

6. The combination, in a safety short-circuit for an arc-lamp, of an armature-bar forming a part of said short-circuit when on front contact, a second armature-bar also forming a part of said short-circuit when on back eontaet, substantially as described.

Signed at New York, in the county of New York and State of New York, this 13th day .of August, A. D. 1883.

CHARLES Ii. BUCKING-HAM. HENRY O. TOW'NSEND.

Yiitnesses:

'lnos. TOOMEY, M. M. FRIEND. 

